U.S. patent number 5,020,550 [Application Number 07/329,782] was granted by the patent office on 1991-06-04 for apparatus for expanding material of an agricultural origin.
This patent grant is currently assigned to Japan Tobacco Inc.. Invention is credited to Masao Kobari, Manabu Takeuchi, Kensuke Uchiyama, Hiromi Uematsu.
United States Patent |
5,020,550 |
Uchiyama , et al. |
June 4, 1991 |
Apparatus for expanding material of an agricultural origin
Abstract
An expanding apparatus of this invention includes a preparatory
vessel that is supplied with material of agricultural origin, for
example, tobacco material. The tobacco material in the preparatory
vessel is supplied to an impregnation vessel through a convey pipe.
Carbon dioxide having an impregnation pressure is supplied to the
impregnation vessel so as to fill the same. A booster mechanism is
associated with the convey pipe to increase the pressure of carbon
dioxide around the tobacco material to a pressure substantially
equal to the impregnation pressure in the impregnation vessel when
the tobacco material is supplied from the preparatory vessel to the
impregnation vessel. The tobacco material impregnated in the
impregnation vessel is discharged to a blow pipe through a delivery
pipe and is expanded by means of a heating medium generated in the
blow pipe. A debooster mechanism is associated with the delivery
pipe to reduce the pressure of carbon dioxide around the tobacco
material to a pressure substantially equal to the pressure in the
blow pipe when the impregnated material is discharged from the
impregnation vessel to the blow pipe.
Inventors: |
Uchiyama; Kensuke (Hiratsuka,
JP), Uematsu; Hiromi (Hiratsuka, JP),
Takeuchi; Manabu (Hiratsuka, JP), Kobari; Masao
(Tokyo, JP) |
Assignee: |
Japan Tobacco Inc. (Tokyo,
JP)
|
Family
ID: |
16170595 |
Appl.
No.: |
07/329,782 |
Filed: |
March 23, 1989 |
PCT
Filed: |
July 27, 1988 |
PCT No.: |
PCT/JP88/00750 |
371
Date: |
March 23, 1989 |
102(e)
Date: |
March 23, 1989 |
PCT
Pub. No.: |
WO89/00821 |
PCT
Pub. Date: |
February 09, 1989 |
Foreign Application Priority Data
|
|
|
|
|
Jul 27, 1987 [JP] |
|
|
62-185427 |
|
Current U.S.
Class: |
131/296;
131/291 |
Current CPC
Class: |
A23P
30/32 (20160801); A24B 3/182 (20130101) |
Current International
Class: |
A24B
3/00 (20060101); A24B 3/18 (20060101); A23P
1/14 (20060101); A24B 003/18 () |
Field of
Search: |
;131/296,900
;426/447,449,445 ;99/323.4,323.9 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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|
|
|
|
|
|
45-11999 |
|
Mar 1970 |
|
JP |
|
49-1879 |
|
Jan 1974 |
|
JP |
|
592829 |
|
Aug 1980 |
|
JP |
|
2115677 |
|
Sep 1983 |
|
GB |
|
Primary Examiner: Millin; V.
Assistant Examiner: Doyle; Jennifer L.
Attorney, Agent or Firm: Nixon & Vanderhye
Claims
We claim:
1. An apparatus for expanding material of agricultural origin
comprising: an impregnating agent source for storing an
impregnating agent to be impregnated in the material to be expanded
and capable of assuming at least a gaseous phase;
a preparatory vessel in communication with ambient atmosphere for
receiving the material to be expanded;
substituting means for substituting air in said preparatory vessel
with a gaseous impregnating agent supplied from said impregnating
agent source;
an impregnation vessel for impregnating the material with the
impregnating agent
supplying means for supplying to said impregnation vessel the
impregnating agent supplied from said impregnating agent source and
having an impregnation pressure higher than atmospheric pressure
and to thereby create an interior atmosphere within said
impregnation vessel that includes the impregnating agent;
convey pipe means for interconnecting said preparatory vessel and
said impregnation vessel and for guiding the material to be
expanded from said preparatory vessel to said impregnation
vessel;
conveying means for conveying the material from said preparatory
vessel to said impregnation vessel through said convey pipe
means;
booster means for filling said convey pipe means with the
impregnating agent supplied from said impregnating agent source
and, immediately before the material is received from said convey
pipe to said impregnation vessel, for increasing the impregnating
agent pressure around said material to a pressure substantially
equal to the impregnation pressure in said impregnation vessel
while maintaining the impregnation pressure within said
impregnating vessel substantially constant;
delivery pipe means, one end of which is connected to said
impregnation vessel, for guiding the material impregnated in said
impregnation vessel;
a blow pipe, connected to the other end of said delivery pipe, for
blowing the impregnated material;
delivering means for delivering the impregnated material from said
impregnation vessel to said blow pipe through said delivery pipe
means;
debooster means for filling said delivery pipe means with
impregnating agent supplied from said impregnating agent source
and, immediately before the impregnated material which was
discharged from said impregnation vessel to said delivery pipe is
then discharged to said blow pipe, for reducing the impregnating
agent pressure around said impregnated material to a pressure
substantially equal to a pressure in said blow pipe while
maintaining the impregnation pressure within said impregnation
vessel substantially constant; and
blowing means operatively associated with said blow pipe, for
generating a flow of a heating medium heated to a predetermined
temperature, and for delivering the flow of said heating medium to
the impregnated material in said blow pipe.
2. An apparatus according to claim 1, wherein said booster means
comprises a rotary valve inserted in said convey pipe means, said
rotary valve being provided with a housing having inlet and outlet
ports respectively connected to convey pipe portions operatively
associated with said preparatory and impregnation vessels, a rotor
having a circumferential surface rotatably and air-tightly in
slidable contact with an inner surface of said housing, a plurality
of pockets formed on said circumferential surface of said rotor at
equal intervals, said plurality of pockets being supplied with the
material supplied from said convey pipe means through said inlet
port together with the impregnating agent and being arranged to
discharge the material and the impregnating agent from said outlet
port, and supplying means for supplying the impregnating agent to
each of said plurality of pockets during movement of said pocket
from said inlet port to said outlet port, the pressure of the
impregnating agent supplied into said pockets being increased
stepwise.
3. An apparatus according to claim 2, wherein said supplying means
comprises a plurality of pressure equalizers for sequentially
allowing communication between said pockets located between said
inlet and outlet ports viewed in a rotational direction of said
rotor of said rotary valve and said pockets located between said
inlet and outlet ports viewed in a direction opposite to the
rotational direction of said rotor during movement of said pockets
from said inlet port to said outlet port.
4. An apparatus according to claim 3, wherein said conveying means
comprises a screw conveyor, arranged in said preparatory vessel,
for feeding out the material from said preparatory vessel to said
convey pipe means, a purge path, formed in said housing of said
rotary valve, for spraying the gaseous impregnating agent toward a
given one of said pockets when said given pocket is connected to
said outlet port, and purge gas means for guiding the gaseous
impregnating agent having a pressure slightly higher than a
pressure in said outlet port from said impregnating agent source to
said purge path.
5. An apparatus according to claim 1, wherein said debooster means
comprises rotary valve inserted in said delivery pipe, said rotary
valve being provided with a housing having inlet and outlet ports
respectively connected to delivery pipe portions associated within
said impregnating vessel and said blow pipe, a rotor having a
circumferential surface rotatably and air-tightly in slidable
contact with an inner surface of said housing, a plurality of
pockets formed on said circumferential surface of said rotor at
equal intervals, said plurality of pockets being supplied with the
material supplied from said impregnation vessel through said inlet
port together with the impregnating agent and being arranged to
discharge the material and the impregnating agent from said outlet
port, and supplying means for supplying the impregnating agent to
each of said plurality of pockets during movement of said pocket
from said inlet port to said outlet port, the pressure of the
impregnation agent supplied into said pockets being decreased
stepwise.
6. An apparatus according to claim 5, wherein said supplying means
comprises a plurality of pressure equalizers for sequentially
allowing communication between said pockets located between said
inlet and outlet ports viewed in a rotational direction of said
rotor of said rotary valve and said pockets located between said
inlet and outlet ports viewed in a direction opposite to the
rotational direction of said rotor during movement of said pockets
from said inlet port to said outlet port.
7. An apparatus according to claim 5, wherein said delivering means
comprises a screw conveyor, arranged in said impregnation vessel,
for feeding out the material from said impregnation vessel to said
delivery pipe, a purge path, formed in said housing of said rotary
valve, for spraying the gaseous impregnating agent toward a given
one of said pockets when said given pocket is connected to said
outlet port, and purge gas means for guiding the gaseous
impregnating agent having a pressure slightly higher than a
pressure in said outlet port from said impregnating agent source to
said purge path.
8. An apparatus according to claim 1, wherein said booster means
comprises:
a pair of ball valves, operatively positioned midway along said
convey pipe means so as to be spaced apart from each other, for
defining therebetween a pressure equalizer chamber within said
convey pipe means which may be isolated from said preparatory and
impregnation vessels when said pair of ball valves are in a closed
position, and for guiding the material from said preparatory vessel
to said pressure equalizer chamber or guiding the material from
said pressure equalizer chamber to said impregnation vessel when a
respective one of said ball valves is in an open position,
pressure equalizing means for supplying to said pressure equalizer
chamber the impregnating agent having a pressure substantially
equal to the impregnation pressure in said impregnation vessel,
and
discharging means for discharging the impregnating agent from said
pressure equalizer chamber and for reducing pressure within said
pressure equalizer chamber to a pressure substantially equal to the
pressure within said preparatory vessel.
9. An apparatus according to claim 8, wherein said pressure
equalizing means fills said pressure equalizer chamber with the
impregnating agent having a pressure slightly higher than the
impregnation pressure in said impregnation vessel.
10. An apparatus according to claim 1, wherein said debooster means
comprises:
a pair of ball valves, operatively positioned midway along said
delivery pipe means so as to be spaced apart from each other, for
defining therebetween a pressure equalizer chamber within said
delivery pipe means which may be isolated from said impregnation
vessel and said blow pipe when said pair of ball valves are in a
closed position, and for guiding the material from said
impregnation vessel to said pressure equalizer chamber or guiding
the material from said pressure equalizer chamber to said blow pipe
when a respective one of said ball valves is in an open
position,
pressure equalizing means for supplying to said pressure equalizer
chamber the impregnating agent having a pressure substantially
equal to the impregnation pressure in said impregnation vessel,
and
discharging means for discharging the impregnating agent from said
pressure equalizer chamber for reducing pressure within said
pressure equalizer chamber to a pressure substantially equal to the
pressure within said blow pipe.
11. An apparatus according to claim 10, wherein said pressure
equalizing means fills said pressure equalizer chamber with the
impregnating agent having a pressure slightly lower than the
impregnation pressure in said impregnation vessel.
12. An apparatus according to claim 2, further comprising an
intermediate vessel, operating positioned in said convey pipe means
for temporarily storing the material, said intermediate vessel
being filled with the impregnating agent having a medium pressure
between a pressure in said preparatory vessel and the impregnation
pressure in said impregnation vessel, and wherein said booster
means comprises a first rotary valve operatively associated with a
portion of said convey pipe means between said impregnation vessel
and said intermediate vessel, and a second rotary valve operatively
associated with another portion of said convey pipe means between
said preparatory vessel and said intermediate vessel.
13. An apparatus according to claim 1, further comprising a cooling
jacket which covers an entire outer surface of said impregnation
vessel and cooling means for supplying a coolant to said cooling
jacket.
14. An apparatus according to claim 1, wherein gaseous carbon
dioxide is supplied into said impregnation vessel as the
impregnating agent.
15. An apparatus according to claim 1, wherein liquefied carbon
dioxide is supplied into said impregnation vessel as the
impregnating agent.
16. An apparatus according to claim 15, wherein said impregnation
vessel is inclined.
Description
FIELD OF THE INVENTION
The present invention relates to an apparatus for expanding
materials of an agricultural origin, and more particularly, to an
apparatus for expanding tobacco material.
BACKGROUND AND SUMMARY OF THE INVENTION
Tobacco is an example of one agricultural material that is
cultivated and harvested. Harvested tobacco leaves have a
relatively high water content and thus cannot be used directly to
manufacture a commercial tobacco product. For this reason, the
harvested tobacco leaves are dried so as to remove moisture
therefrom. In general, therefore, only dried tobacco leaves may be
preserved or used to manufacture a commercial tobacco product.
Tobacco leaves however, shrink extremely when they are dried. The
tobacco material manufactured from such dried tobacco leaves also
experiences shrinkage (i.e. reduction in volume). If tobacco
material of reduced volume is used to manufacture cigarettes, for
example, the amount of tobacco material per cigarette must be
increased thereby deleteriously affecting cigarette
productivity.
Due to the above circumstances, therefore, the dried tobacco
material is expanded to increase the volume of the tobacco
material, prior to use of the tobacco material to manufacture
cigarettes, thereby improving cigarette productivity.
Conventional apparatus for expanding tobacco material are described
in Japanese Patent Publication No. 49-1879 and Japanese Patent
Disclosure (Kokai) No. 50-107197. The apparatus described in
Japanese Publication No. 49-1879 includes an impregnation vessel
used to impregnate the tobacco material with an organic solvent.
More specifically, organic solvent is separated into liquid and
gaseous phases. The tobacco material in the impregnation vessel is
first dipped in the liquid-phase organic solvent, and then
subsequently is contacted with the gaseous-phase organic solvent.
The tobacco material impregnated with organic solvent is removed
from the impregnation vessel and is heated. Upon heating, organic
solvent contained in the impregnated tobacco material is evaporated
as a gas from the tobacco material. By the evaporation of organic
solvent, the tobacco material is expanded.
In the apparatus disclosed in Japanese Patent Disclosure (Kokai)
No. 50-107197, liquefied carbon dioxide is used as an expanding
agent in order to expand the tobacco material. In the expanding
apparatus disclosed in Japanese Patent Publication No. 50-107197
the principle of expanding the tobacco material is the same as that
in Japanese Patent Publication No. 49-1879 discussed above. In this
regard, tobacco material impregnated with carbon dioxide is heated
to evaporate carbon dioxide gas from the tobacco material, and
thereby expand the tobacco material.
Since the expanding apparatus disclosed in Japanese Patent
Publication No. 49-1879 uses liquefied organic solvent as an
expanding agent, the internal pressure of the impregnation vessel
required to impregnate the tobacco material with organic solvent
can be relatively low. In such a apparatus using liquefied organic
solvent, the tobacco material can be charged continuously in the
impregnation vessel so as to impregnate the tobacco material with
organic solvent, and thus expansion of the tobacco material can be
continuously performed.
Freon.TM. halogenated hydrocarbons are conventionally used as
expanding agents. However, since Freon.TM.hydrocarbons are a known
environmental pollutant, the amount of Freon.TM. hydrocarbon
production has recently been decreased, with the result being that
the cost of Freon.TM. has increased. For this reason, when an
expanding apparatus using Freon.TM. hydrocarbon is employed in the
tobacco production line, the cost of such tobacco is inevitably
increased with an increase in the cost of the Freon.TM.
hydrocarbons.
The expanding apparatus described in Japanese Patent Disclosure
(Kokai) No. 50-107197 uses liquefied carbon dioxide in place of
Freon.TM. halogenated hydrocarbons as an expanding agent. Although
the disadvantages of Freon.TM. can be eliminated, the advantage
thereof (i.e., a continuous treatment) is lost. When carbon dioxide
as an expanding agent is used to impregnate the tobacco material to
a desired level, the internal pressure of the impregnation vessel
(i.e., the pressure of carbon dioxide) must be kept at a high
pressure regardless of the liquid- and gaseous-phase carbon
dioxide. For this reason, in expanding apparatus using carbon
dioxide, the internal pressure of the impregnation vessel must be
kept at a high pressure. In addition, the tobacco material to be
expanded cannot be continuously charged into the impregnation
vessel. As a result, in the expanding apparatus using carbon
dioxide, the expansion treatment is inevitably a batch process.
Therefore, such an apparatus is not suitable for expanding a large
amount of tobacco material. When carbon dioxide is used as an
expanding agent, the amount of carbon dioxide impregnated in the
tobacco material is relatively small. For this reason, the tobacco
material impregnated with carbon dioxide must be immediately
heated, preferably within two minutes. Otherwise, desired expansion
of the tobacco material cannot be achieved. Under these
circumstances, it is difficult to use the batch type expanding
apparatus using carbon dioxide as an expanding agent in practical
(i.e., industrial) applications.
When liquefied dioxide is used as an expanding agent, a large
amount of dry ice is contained in the tobacco material removed from
the impregnation vessel to the outer atmosphere. For this reason, a
large amount of liquefied carbon dioxide is lost. The amount of
carbon dioxide supplied to the impregnation vessel (i.e. the amount
of carbon dioxide used) is inevitably increased. In addition, the
tobacco material must be heated at a higher temperature during
heating of the tobacco material.
It is an object of the present invention to provide an apparatus
for expanding materials of agricultural origin, such as foodstuffs,
and the like to be expanded, wherein carbon dioxide can be properly
used as an impregnating agent, i.e., an expanding agent, and
expansion of the material can be performed continuously.
In order to achieve the above object of the present invention,
there is provided an apparatus for expanding material of
agricultural origin, comprising a preparatory vessel which receives
the material and is open to the outer atmosphere. Air in the
preparatory vessel is substituted with a gaseous impregnating agent
supplied from an impregnating agent source. The material in the
preparatory vessel is introduced into an impregnation vessel
through a convey pipe. An impregnating agent having a pressure
higher than atmospheric pressure is supplied from the impregnating
agent source so that the impregnation vessel is filled with the
impregnating agent.
The expanding apparatus also comprises booster means for filling
the impregnating agent in the convey pipe and boosting the pressure
of the impregnating agent around the material to a pressure
substantially equal to that in the impregnation vessel immediately
before the supply of the material from the convey pip to the
impregnation vessel, while the pressure in the impregnation vessel
is kept unchanged.
One end of a delivery pipe is connected to the impregnation vessel
to discharge the material impregnated with the impregnating agent
in the impregnation vessel. The other end of the delivery pipe is
connected to a blow pipe for conveying the impregnated material
with air. A flow of a heating medium heated to a predetermined
temperature is generated in the blow pipe.
The expanding apparatus also comprises a debooster means having a
function opposite to that of the booster means. The debooster means
fills the impregnating agent from the impregnating agent source in
the delivery pipe and reduces the pressure of the impregnating
agent around the impregnated material to a pressure substantially
equal to that of the blow pipe, immediately before delivery of the
impregnated material from the delivery pipe to the blow pipe, while
the pressure of the impregnation vessel is kept unchanged.
According to the expanding apparatus of the present invention, the
material is charged in the impregnation vessel from the preparatory
vessel through the convey pipe and is impregnated in the
impregnation vessel. The impregnated material is discharged from
the impregnation vessel to the blow pipe through the delivery pipe.
The impregnated material discharged in the blow pipe is heated by
the heating medium flowing in the blow pipe while being conveyed by
the flow of the heating medium. During blowing, the impregnated
material is expanded. That is, the agent impregnated in the
material is evaporated by heating of the material, and evaporation
of the impregnating agent allows expansion of the material.
According to the expanding apparatus of the present invention as
described above, the booster means is arranged to supply the
material from the preparatory vessel to the impregnation vessel
through the convey pipe, and the debooster means is arranged to
discharge the impregnated material from the impregnation vessel to
the blow pipe through the delivery pipe. Therefore, the material
can be continuously supplied to the impregnation vessel or
discharged therefrom while the pressure of the impregnation vessel
is kept unchanged. Therefore, impregnation of the material can be
continuously performed, and expansion of the impregnated material
can also be continuously performed.
The pressure of the impregnation vessel can be kept unchanged
although continuous impregnation in the impregnation vessel is
performed. Therefore, carbon dioxide which requires a high
impregnation pressure can be used as an impregnating agent.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1A to 5 show a first embodiment of the present invention, in
which:
FIGS. 1A and 1B are schematic views showing halves of an overall
structure of an expanding apparatus according to the present
invention;
FIGS. 2 to 5 are sectional views showing first to fourth rotary
valves used in the expanding apparatus shown in FIG. 1,
respectively;
FIGS. 6A and 6B are schematic views showing halves of an expanding
apparatus according to a second embodiment of the present
invention; and
FIGS. 7A and 7B are schematic views showing halves of an expanding
apparatus according to a third embodiment of the present
invention.
DETAILED DESCRIPTION OF THE PREFERRED EXEMPLARY EMBODIMENTS
An expanding apparatus according to one embodiment of the present
invention will be described with reference to FIGS. 1 to 5.
FIGS. 1A and 1B collectively shown an overall structure of the
expanding apparatus according to the present invention. The
expanding apparatus comprises humidifier 1 which is of the rotary
drum type having a charging port 2 for receiving a material
subjected to expansion, e.g., tobacco material. Conveyor 3 extends
outside humidifier 1 near charging port 2 to convey the tobacco
material. The tobacco material conveyed by conveyor 3 is charged in
humidifier 1 through charging port 2. The tobacco material is
prepared by cutting dried tobacco leaves into pieces each having a
predetermined size. Humidifying nozzle 4 is disposed in humidifier
1. Nozzle 4 is connected to steam pipe 5, and steam pipe 5 is
connected to a water/steam source (not shown) through a cover of
humidifier 1. Water or steam is sprayed from humidifying nozzle 4
to the tobacco material supplied to humidifier 1. At the same time,
the rotary drum of humidifier 1 is rotated around its axis, thereby
appropriately dampening the tobacco material. Reference numeral 6
denotes an opening/closing valve arranged midway along steam pipe
5.
Preparatory vessel 7 is arranged below humidifier 1. Preparatory
vessel 7 comprises a horizontally disposed cylindrical vessel.
Vessel 7 receives the tobacco material discharged from humidifier 1
upon rotation of humidifier 1. Chute 8 is disposed near the other
end of humidifier 1 to receive the charged tobacco material. Chute
8 is connected to reception port 9 formed at one end of preparatory
vessel 7. Therefore, the tobacco material dampened in humidifier 1
can be fed from humidifier 1 to vessel 7 through chute 8 and
reception port 9.
Impregnation vessel 10 is disposed below preparatory vessel 7.
Vessel 10 comprises a cylindrical vessel in the same manner as
preparatory vessel 7 and is disposed horizontally except that
impregnation vessel 10 is a pressure vessel which can withstand
high pressures.
Preparatory vessel 7 is connected to impregnation vessel 10 through
convey pipe 11. The upper end of convey pipe 11 is connected to
delivery port 12 formed at the other end of preparatory vessel 7.
The lower end of pipe 11 is connected to reception port 13 formed
at one end of impregnation vessel 10.
In the first embodiment, convey pipe 11 substantially comprises
intermediate vessel 14, as is apparent from FIG. 1. Intermediate
vessel 14 is a pressure vessel which has a cylindrical shape as in
impregnation vessel 10 and disposed horizontally. Reception port 15
formed at one end of intermediate vessel 14 is connected to
delivery port 12 of preparatory vessel 7. Delivery port 16 formed
at the other end of intermediate vessel 14 is connected to
reception port 13 of impregnation vessel 10.
Screw conveyors 17 and 18 are disposed in preparatory and
intermediate vessels 7 and 14, respectively. Screw conveyors 17 and
18 can be rotated by motors 19 and 20 having reduction gear
mechanisms, respectively. Screw conveyors 17 and 18 constitute part
of a convey mechanism for conveying the tobacco material from
preparatory vessel 7 to impregnation vessel 10 through intermediate
vessel 14. More specifically, the tobacco material in preparatory
vessel 7 is conveyed to delivery port 12 upon rotation of screw
conveyor 17 and is then supplied from delivery port 12 to
intermediate vessel 14 through its reception port 15. The tobacco
material thus supplied to intermediate vessel 14 is conveyed to
delivery port 16 upon rotation of screw conveyor 18 and is then
supplied from delivery port 16 to impregnation vessel 10 through
its reception port 13.
The expanding apparatus comprises impregnating agent source 21 for
supplying an impregnating gas such as carbon dioxide gas. Source 21
comprises storage tank 22 for storing liquefied carbon dioxide.
Tank 22 is connected to recovery gas holder 24 through pipe 23.
Evaporator 25, pressure reducing valve 26, and level adjusting
valve 27 are inserted in pipe 23 from the side of tank 22.
Evaporator 25 evaporates liquefied carbon dioxide supplied from
tank 22. Therefore, carbon dioxide gas is supplied to recovery gas
holder 24 through pipe 23.
The pressure of carbon dioxide gas supplied to recovery gas holder
24 is reduced to a predetermined level by pressure reducing valve
26. Level adjusting valve 27 opens or closes pipe 23 in accordance
with a level of a diaphragm which defines a chamber in holder 24,
thereby maintaining the level of the diaphragm at a predetermined
level.
Recovery gas holder 24 is connected to gas tank 29 through pipe 28.
Strainer 30 and booster 31 are inserted in pipe 28 from the side of
recovery gas tank 24. Booster 31 is actuated in accordance with a
pressure in gas tank 29. The pressure of carbon dioxide gas in gas
tank 29 is maintained at a predetermined pressure level or higher,
i.e., an impregnation pressure or higher of carbon dioxide gas to
be supplied to impregnation vessel 10.
Gas tank 29 is connected to impregnation vessel 10 through
impregnating gas supply pipe 32. Heat exchanger 33 and pressure
control valve 34 are inserted in pipe 32 from the upstream side.
Therefore, carbon dioxide gas supplied from gas tank 29 passes
through heat exchanger 33, so that the temperature of the gas is
decreased to a predetermined temperature. The resultant gas is then
supplied to impregnation vessel 10. Pressure control valve 34 is
actuated by the pressure in impregnation vessel 10 to maintain a
constant pressure of carbon dioxide gas in vessel 10. Pressure
control valve 34 generally maintains the pressure of carbon dioxide
gas to be 10 kg/cm.sup.2 to 50 kg/cm.sup.2 (gauge pressure), and 30
kg/cm.sup.2 in this embodiment. Heat exchanger 33 generally
maintains the temperature of carbon dioxide gas in impregnation
vessel 10 to be -40.degree. C. to 15.degree. C., and to be a
temperature which prevents freezing of moisture contained in carbon
dioxide gas, e.g., 5.degree. C. in this embodiment.
In order to cause heat exchanger 33 to cool carbon dioxide gas,
heat exchanger 33 is connected to coolant tank 37 through coolant
circulating pipes 35 and 36. Circulation pump 38, temperature
control heater 39, a three-way valve 40 are inserted in pipe 35.
Heater 39 controls a cooling temperature of carbon dioxide gas with
high precision. Three-way valve 40 controls a flow of a coolant in
pipes 35 and 36.
According to heat exchanger 33 described above, when carbon dioxide
gas passes through heat exchanger 33, moisture contained in carbon
dioxide gas is not frozen in heat exchanger 33. Therefore, clogging
of impregnating gas supply pipe 32 by freezing of the moisture can
be prevented.
When the tobacco material is impregnated with carbon dioxide gas at
a pressure of 15 kg/cm.sup.2 of impregnation vessel 10, the
internal temperature of vessel 10 is preferably kept at -10.degree.
C. or less. In this case, carbon dioxide gas supplied from gas tank
29 to impregnation vessel 10 through impregnating gas supply pipe
32 must also be cooled to a temperature of -10.degree. C. or less.
The following two cooling methods are available.
According to the first cooling method, in order to prevent moisture
dissolved in liquefied carbon dioxide in storage tank 22 and
moisture evaporated and recovered from the tobacco material during
conveyance from being frozen in heat exchanger 33 and hence prevent
blocking of the gas flow, dehumidifier 41 is inserted on the
upstream side of heat exchanger 33 to perfectly eliminate the
moisture from the gas. The dry gas is then cooled by heat exchanger
33 to a predetermined temperature, and then cooled gas is supplied
to impregnation vessel 10.
According to the second cooling method, dehumidifier 41 is not
inserted on the upstream side of heat exchanger 33. An outlet
temperature of heat exchanger 33 is set to be about 2.degree. C.,
and the gas is cooled to prevent its freezing. However, this
temperature is higher than the predetermined temperature in the
impregnation vessel. Therefore, the gas is cooled by the following
operation. The pressure of gas tank 29 is kept at 35 kg/cm.sup.2
and the gas is supplied to the impregnation vessel through pressure
control valve 34. In this case, the gas pressure is abruptly
reduced from 35 kg/cm.sup.2 to 15 kg/cm.sup.2, so that the gas
supplied to the impregnation vessel is cooled from about 2.degree.
C. to -10.degree. C. or less by heat-insulating expansion.
Impregnation vessel 10 and intermediate vessel 14 are connected
through first rotary valve 42 constituting part of the booster
mechanism, the structure of which will be described with reference
to FIG. 2.
First rotary valve 42 has circular housing 43. Inlet port 44 is
formed at the upper portion of housing 43 and is connected to
delivery port 16 of intermediate vessel 14. Outlet port 45 is
formed at the lower portion of housing 43 and is connected to
reception port 13 of impregnation vessel 10. Liner 46 is formed on
the inner surface of housing 43. Openings which respectively
communicate with inlet and outlet ports 44 and 45 are formed in
liner 46.
Five connecting holes 47a, 47b, 47c, 47d, and 47e are formed in
liner 46 between inlet and outlet ports 44 and 45 at equal angular
intervals sequentially in the clockwise direction. Similarly, five
connecting holes 47f, 47g, 47h, 47i, and 47j are formed in liner 46
between outlet and inlet ports 45 and 44 at equal angular intervals
in the same manner as in holes 47a to 47e. Communication holes 48a
to 48j which respectively communicate with holes 47a to 47j are
formed in housing 43. As can be apparent from FIG. 2, communication
hole 48a is connected to communication hole 48i through first
pressure equalizer 49. Communication hole 48b communicates with
communication hole 48h through second pressure equalizer 50.
Similarly, communication hole 48c is connected to communication
hole 48g through third pressure equalizer 51, and communication
hole 48d is connected to communication hole 48f through fourth
pressure equalizer 52. Communication hole 48e is connected to
impregnating gas supply pipe 32 through communication pipe 53.
Communication pipe 53 is branched from a downstream portion of
impregnating gas supply pipe 32 with respect to pressure control
valve 34. Communication hole 48j is connected to supply portion 55
of intermediate vessel 14 through communication pipe 54 (FIG.
1).
Rotor 56 which can be slidably rotated along the inner surface of
liner 46 is disposed in housing 43. Rotor 56 is mounted on output
shaft 57 of a drive motor (not shown). Rotor 56 is rotated by this
drive motor in the clockwise direction of an arrow in FIG. 2.
Fourteen pockets 58 are formed on the circumferential surface at
equal intervals. As is apparent from FIG. 2, each pocket 58 has a
sector cross section expanding outward from rotor 56. Pockets 58
are sequentially connected to inlet and outlet ports 44 and 45 and
connecting holes 47a to 47j, i.e., communication holes 48a to 48j
upon rotation of rotor 56.
The pressure of carbon dioxide gas, i.e., impregnating gas in
impregnation vessel 10 is kept at 30 kg/cm.sup.2 (gauge pressure).
Upon rotation of rotor 56, the impregnating gas is supplied from
impregnation vessel 10 to pocket 58 communicating with outlet port
45. The pressure in pocket 58 communicating with outlet port 45 is
the same as that of impregnation vessel 10. Pocket 58 connected to
impregnation vessel 10 can be sequentially connected to connecting
holes 47f to 47j, i.e., communication holes 48f to 48j upon
rotation of rotor 51. In this case, since holes 48f, 48g, 48h, and
48i communicate with holes 48d, 48c, 48b, 48a through the pressure
equalizers, respectively. The pressure of the impregnating gas in
pocket 58 having communicated with outlet port 45 is reduced when
this pocket 58 is sequentially connected to holes 48f to 48j. When
pocket 58 is connected to communication hole 48j, the impregnating
gas in pocket 58 is supplied to intermediate vessel 14 through pipe
54 and supply portion 55. Upon rotation of rotor 56, the
impregnating gas is continuously supplied from impregnation vessel
10 to intermediate vessel 14. Therefore, when the expanding
apparatus is started, the pressure of the impregnating gas in
intermediate vessel 14 is gradually increased.
As shown in FIG. 1, supply portion 55 in intermediate vessel 14 is
connected to recovery gas holder 24 through return pipe 59.
Strainer 60 and pressure control valve 61 are sequentially inserted
in pipe 59 from the side of intermediate vessel 14. Valve 61 is
actuated by the pressure of the impregnating gas in intermediate
vessel 14, i.e., the pressure of the impregnating gas (as a pilot
pressure) in return pipe 59 between supply portion 55 and pressure
control valve 61 in intermediate vessel 14. Pressure control valve
61 has a function for setting the pressure of the impregnating gas
in intermediate vessel 14 to be a predetermined value, e.g., 15
kg/cm.sup.2 (gauge pressure).
When the impregnating gas is supplied from impregnation vessel 10
to intermediate vessel 14 through communication pipe 54 and supply
portion 55, the pressure of the impregnating gas in intermediate
vessel 14 is gradually increased. The pressure of intermediate
vessel 14 is controlled to be 15 kg/cm.sup.2 (gauge pressure) by
pressure control valve 61.
When the pressure of the impregnating gas in intermediate vessel 14
is kept at 15 kg/cm.sup.2 (gauge pressure), the pressure of the
impregnating gas in impregnation vessel 10 is applied to pockets 58
of rotor 56 which sequentially pass through outlet port 45 of first
rotary valve 42. At the same time, the pressure of the impregnating
gas in intermediate vessel 14 is applied to pockets 58 of rotor 56
which pass through inlet port 44. Each pocket 58 of rotor 56 which
has passed inlet port 44 is sequentially connected to communication
holes 48a to 48d upon rotation of rotor 56. As previously
described, these holes 48a, 48b, 48c, and 48d communicate with
holes 48i, 48h, 48g, and 48f, respectively. Each pocket 58 of rotor
56 which has passed inlet port 44 is sequentially connected to
communication holes 48a to 48d and pockets 58 located on the left
half of rotor 56 in FIG. 2 through pipes 49 to 52. The pressure of
each pocket 58 located on the left half of rotor 56 is gradually
increased from inlet port 44 to outlet port 45. The pressure of the
impregnating gas in each pocket 58 which has passed inlet port 44
is increased stepwise. More specifically, when viewed in the
clockwise direction of rotor 56, boosting stages from inlet port 44
to outlet port 45 are five stages, while deboosting stages from
outlet port 45 to inlet port 44 are five stages. The pressures of
two pockets 58 connected through the corresponding pressure
equalizer are the same. Assuming that the volumes of pockets 58 are
equal to each other and that the volumes of pipes 49, 50, 51 and 52
are also equal to each other, then in each of the boosting and
deboosting stages, the pressures of the impregnating gases in
pockets 58 are equally increased or decreased by every 1/5 of 15
kg/cm.sup.2 as a pressure difference between inlet and outlet ports
44 and 45, that is, every 3 kg/cm.sup.2. As a result, when rotor 56
is located at the angular position shown in FIG. 2, the pressures
of the impregnating gas in pockets 58 are represented by numeric
values written in pockets 58. In the state shown in FIG. 2, pocket
58 connected to communication hole 48e is always connected to
impregnating gas supply pipe 32 through hole 48e and pipe 53. The
pressure of the impregnating gas in pocket 58 is set to be 30
kg/cm.sup.2. Pocket 58 connected to communication hole 48j is
further connected to intermediate vessel 14, so that the pressure
of the impregnating gas therein is 15 kg/cm.sup.2.
Pocket purge path 62 located on the hole 48f side and extending
toward rotor 56 is formed in outlet port 45 of first rotary valve
42. One end of path 62 is open toward the circumferential surface
of rotor 56. The other end of path 62 is connected to impregnating
gas supply pipe 32 through hole 63 formed in housing 43 and through
high-pressure purge pipe 64. More specifically, pipe 64 is
connected to a portion of pipe 32 between heat exchanger 33 and
pressure control valve 34: Pressure reducing valve 65 is inserted
midway along pipe 64. Valve 65 supplies the impregnating gas having
a pressure higher than that in impregnation vessel 10 to pocket
purge path 62.
Since first rotary valve 42 is disposed between intermediate vessel
14 and impregnation vessel 10, the tobacco material in intermediate
vessel 14 is guided to delivery port 16. The tobacco material is
then supplied from delivery port 16 to inlet port 44 of first
rotary valve 42. Upon rotation of rotor 56, the tobacco material is
supplied from inlet port 44 to each pocket 58 of rotor 56. Each
pocket 58 supplied with the tobacco material is conveyed toward
outlet port 45 upon rotation of rotor 56. When each pocket 58
reaches outlet port 45, the tobacco material therein is supplied to
impregnation vessel 10 through outlet port 45 and reception port 13
of vessel 10. During movement of pockets 58 filled with the tobacco
material from inlet port 44 of valve 42 to outlet port 45, the
pressures of the impregnating gas in pockets 58 are increased
stepwise, as described above. In addition, immediately before each
pocket 58 is connected to outlet port 45, pocket 58 is connected to
impregnating gas supply pipe 32 through communication hole 48e and
communication pipe 53, and the pressure of pocket 58 is set to be
equal to that in impregnation vessel 10. As a result, when pocket
58 filled with the tobacco material is connected to impregnation
vessel 10, the pressure of pocket 58 is equal to that of vessel 10.
The tobacco material in each pocket 58 can therefore be smoothly
supplied to vessel 10 by the weight of tobacco material. More
specifically, use of first rotary valve 42 prevents a substantial
decrease in pressure of the impregnating gas in vessel 10 even if a
pressure difference is present between vessels 10 and 14, so that
the tobacco material can be smoothly transferred from vessel 14 to
vessel 10.
In this embodiment, since pocket purge path 62 is formed in outlet
port 45 of first rotary valve 42, the impregnation gas having a
pressure slightly higher than that in outlet port 45 can be sprayed
from one end of path 62 toward the circumferential surface of rotor
56, i.e., toward each pocket 58. Upon spraying, the tobacco
material in each pocket 58 can be properly discharged toward outlet
port 45.
After the tobacco material passes through outlet port 45, the
pressures of empty pockets 58 are decreased stepwise, as previously
described, during moving toward inlet port 44 upon rotation of
rotor 56. Immediately before pocket 58 is connected to inlet port
44 again, its pressure is set to be equal to that of intermediate
vessel 14. As a result, the tobacco material can be smoothly
supplied from intermediate vessel 14 to each 5 pocket of rotor 56
upon rotation of rotor 56.
Second rotary valve 66, like first rotary valve 42, is disposed
between intermediate vessel 14 and preparatory vessel 7. Valve 66
together with valve 42 constitutes part of the booster mechanism.
Valve 66 is best illustrated in FIG. 3. As is apparent from FIG. 3,
valve 66 has substantially the same structure as that of valve 42.
The same reference numerals as in first rotary valve 42 denote the
same parts and members in second rotary valve 66, and a detailed
description thereof will be omitted. Only differences between
valves 42 and 66 will be described below.
In second rotary valve 66, communication pipe 67a corresponding to
communication pipe 53 of first rotary valve 42 is connected to
return pipe 59 extending from intermediate vessel 14, as shown in
FIG. 1. Medium-pressure purge pipe 68 corresponding to
high-pressure purge pipe 64 of valve 42 is connected to
impregnating gas supply pipe 32 in the same manner as in pipe 64.
Pressure reducing valve 69 is inserted in pipe 68. Valve 69
supplies the impregnating gas having a pressure slightly higher
than that in vessel 14 to pocket purge path 62 of second rotary
valve 66.
In second rotary valve 66, communication pipe 70 corresponding to
communication pipe 54 of first rotary valve 42 is connected to
preparatory vessel 7 and recovery gas holder 24, as is apparent
from FIG. 1. Opening/closing valve 71 is inserted in pipe 70. When
valve 71 is open, the impregnating gas is supplied from second
rotary valve 66 to vessel 7 through pipe 70. In this case, the
pressure of the impregnating gas supplied to vessel 7 is apparently
higher than the atmospheric pressure. Therefore, the impregnating
gas is filled in vessel 7. However, since vessel 7 communicates
with the outer atmosphere, its internal pressure is substantially
the same as the atmospheric pressure. A pressure difference between
preparatory vessel 7 and intermediate vessel 14 is 15 kg/cm.sup.2
(gauge pressure). Therefore, the pressures of pockets 58 are
represented by values written in these pockets 58 in FIG. 3.
According to the second rotary valve 66, the tobacco material is
supplied from preparatory vessel 7 to pockets upon rotation of
rotor 56 and can be properly supplied from pockets 58 to
intermediate vessel 14 in the same manner as in first rotary valve
42. In addition, according to valve 66, pressure loss of vessel 14
is also prevented.
As shown in FIG. 1, cooling jackets 72 and 73 are formed on the
outer surfaces of impregnation vessel 10 and intermediate vessel
14, respectively. Jackets 72 and 73 are connected to coolant supply
pipe 71 through corresponding branched supply pipes 74 and 75. Pipe
171 is connected to tank 37, and circulation pump 38a is arranged
in pipe 171 near tank 37. Cooling jackets 72 and 73 are connected
to return pipe 80 through corresponding branched return pipes 78
and 79. Return pipe 80 is connected to coolant tank 37. Since
cooling jackets 72 and 73 are formed on vessels 10 and 14,
respectively, a coolant is supplied from coolant tank 37 to cooling
jackets 72 and 73 and the temperature of the impregnating gas in
vessels 10 and 14 can be kept constant.
Although not shown in FIGS. 2 and 3 but as schematically shown in
FIG. 1, cooling jackets 81 are mounted on first and second rotary
valves 42 and 66 to cover them. These jackets 81 are connected to
branched supply pipe 75, i.e., coolant supply pipe 171. At the same
time, jackets 81 are connected to return path 80 through paths 82
and 83. Since jackets 81 are formed on valves 42 and 43,
respectively, an increase in temperature upon driving of valves 42
and 66 can be prevented. Therefore, the temperature of the
impregnating gas in impregnation vessel 10 and intermediate vessel
14 can be kept constant with high precision.
Delivery port 84 is formed at the other end of impregnation vessel
10. Endless blow pipe 85 is disposed below delivery port 84. Blow
pipe 85 and delivery port 84 of impregnation vessel 10 are
connected through delivery pipe 86. Large-diameter pipe portion 87
is disposed midway along delivery pipe 86. Pipe portion 87 has an
inverted flask-like shape such that an upper portion has a large
diameter and the diameter is reduced toward its lower portion. Pipe
portion 87 is connected to return pipe 59 through pipe 88.
Therefore, the pressure of pipe portion 87 is equal to that of
intermediate vessel 14, i.e., 15 kg/cm.sup.2 (gauge pressure).
A delivery mechanism, e.g., screw conveyor 89, for delivering the
tobacco material from impregnation vessel 10 to blow pipe 85
through delivery pipe 86 is arranged in impregnation vessel 10.
Screw conveyor 89 is the same as screw conveyors 17 and 18. Screw
conveyor 89 is rotated by motor 90 with a reduction gear mechanism.
When screw conveyor 89 is arranged inside impregnation vessel 10,
the tobacco material therein can be conveyed toward delivery port
84 upon rotation of conveyor 89. The tobacco material is guided
from delivery port 84 to blow pipe 85 through delivery pipe 86.
Third rotary valve 91 constituting part of a debooster mechanism is
inserted between delivery port 84 of impregnation vessel 10 and
large-diameter pipe portion 87 of delivery pipe 86. As is apparent
from FIG. 4, valve 91 has the same structure as that of first and
second rotary valve 42 and 66. Only differences between valve 91
and valve 42 or 66 will be described below.
In third rotary valve 91, communication hole 48a communicates with
communication hole 48j through pressure equalizer 92. Communication
hole 48b communicates with communication hole 48i through pressure
equalizer 93. Communication hole 48c communicates with
communication hole 48h through pressure equalizer 94, and
communication hole 48d communicates with communication hole 48g
through pressure equalizer 95. Communication hole 48e communicates
with communication hole 48f through pressure equalizer 96. As is
apparent from FIGS. 1 and 4, pressure equalizer 92 is connected to
impregnating gas supply pipe 32 through pipe 97, and pressure
equalizer 96 is connected to return pipe through pipe 98.
Pocket purge path 62 of third rotary valve 91 is connected to a
downstream portion (with respect to pressure reducing valve 69) of
medium-pressure purge pipe 68 through medium-pressure purge pipe
99. A connection between medium-pressure purge pipes 68 and 99 is
not illustrated for illustrative convenience in FIG. 1.
According to third rotary valve 91, the pressure of each pocket 58
during its movement from high-pressure inlet port 44 to
low-pressure outlet port 45 upon rotation of rotor 56 is gradually
reduced since it is sequentially connected to communication holes
48a to 48e. During movement of each pocket 58 from low-pressure
outlet port 45 to high-pressure inlet port 44, it is sequentially
connected to communication holes 48f to 48j and is gradually
increased. As a result, a pressure distribution of pockets 58 in
third rotary valve 91 is as illustrated in FIG. 4. In FIG. 4, the
pressures are represented by values written in pockets 58.
Fourth rotary valve 100 (best illustrated in FIG. 5) is inserted
between blow pipe 85 and large-diameter pipe portion 87 of delivery
pipe 86. Fourth rotary valve 100 together with third rotary valve
91 constitutes part of the debooster mechanism. Valve 100 has
substantially the same structure as each of the above-mentioned
rotary valves. Layout of pressure equalizers is the same as in
first and second rotary valve 42 and 66. That is, rotary valve 100
has pressure equalizers 49, 50, 51, and 52 which are the same as
those in first and second rotary valves 42 and 66. In fourth rotary
valve 100, communication pipe 101 corresponding to communication
pipe 53 or 67 in first or second rotary valve 42 or 66 is connected
to recovery gas holder 24 through communication pipe 70 of second
rotary valve 66, as shown in FIG. 1. Communication pipe 102 of
fourth rotary valve 100 which corresponds to communication pipe 54
or 70 of rotary valve 42 or 66 is connected to return pipe 59. In
fourth rotary valve 100, low-pressure purge pipe 103 connected to
pocket purge path 62 is connected to medium-pressure purge pipe 99
of third rotary valve 91 through a pressure reducing valve (not
shown). This pressure reducing valve supplies the impregnating gas
having a pressure slightly higher than the atmospheric pressure to
pocket purge path 62 of fourth rotary valve 100.
In the above description, in third and fourth rotary valves 91 and
100, the impregnating gas having a predetermined pressure is
supplied to pocket purge path 62 in the same manner as in first and
second rotary valves 42 and 66. However, if the tobacco material
can be smoothly discharged from third and fourth rotary valves 91
and 100 without spraying the impregnating gas from pocket purge
path 62 can be stopped. In this case, holes 63 of third and fourth
rotary valves 91 and 100 are closed.
As shown in FIG. 1, cooling jackets 80 are formed on the outer
surfaces of third and fourth rotary valves 91 and 100 and
large-diameter pipe portion 87 in the same manner as in first and
second rotary valves 42 and 66, as shown in FIG. 1. Jackets 80 on
third rotary valve 91 and large-diameter pipe portion 87 are
connected to branched supply pipe 74 and to branched return pipe 78
through a pipe. Jacket 80 on fourth rotary valve 100 is connected
to coolant supply pipe 71 and return pipe 80 through pipes, as
shown in FIG. 1.
Air locker 103 is inserted between fourth rotary valve 100 and blow
pipe 85, as needed. Air locker 103 is simply connected to fourth
rotary valve 100 and blow pipe 85 to transfer the tobacco material
from valve 100 to blow pipe 85 and prevents the heat transfer
between fourth rotary valve 100 and blow pipe 85.
If the pressure of blow pipe 85 is equal to the atmospheric
pressure, the interior of outlet port 45 of fourth rotary valve 100
communicates with the outer atmosphere through air locker 103.
In this state, when fourth rotary valve 100 is driven, the
pressures of pockets 58 which receive the pressure from
large-diameter pipe portion 87 through inlet port 44 upon rotation
of rotor 56 are reduced in five stages during moving of pockets
from inlet port 44 to outlet port 45. The pressures of pockets 58
which receive the pressure from blow pipe 85 through outlet port 45
are reduced in five stages during moving of pockets from outlet
port 45 to inlet port 44. The pressure distribution of pockets 58
is given by pressure values written in pockets 58 in FIG. 5.
Since third and fourth rotary valves 91 and 100 are arranged in
delivery pipe 86, the tobacco material delivered from delivery port
84 of impregnation vessel 10 is fed from delivery port 84 to outlet
port 45 through pockets 58 of third rotary valve 91. The tobacco
material is then conveyed from outlet port 45 to large-diameter
pipe portion 87. The tobacco material is fed from pipe portion 87
to outlet port 45 of fourth rotary valve 100 through pockets 58 of
fourth rotary valve 100. Finally, the tobacco material is guided
from outlet port 45 to blow pipe 85 through air locker 103. In
third and fourth rotary valves 91 and 100, unlike in first and
second rotary valves 42 and 66, the pressures in pockets 58 which
receive and convey the tobacco material are reduced stepwise, as
can be apparent from the above description. The tobacco material
can be smoothly delivered from impregnation vessel 10 to blow pipe
85. In addition, the pressure loss in impregnation vessel 10 during
delivery of the tobacco material, i.e., the pressure loss of the
impregnating gas can be prevented.
Blower 104 is inserted in blow pipe 85. Blower 104 generates a flow
of a heating medium in a direction of an arrow (FIG. 1) in blow
pipe 85. In blow pipe 85, flow control valve 105 and heater 106
serving as a heating mechanism are sequentially inserted between
blower 104 and air locker 103. Exhaust pipe 107 is branched from a
portion of blow pipe 85 between blower 104 and flow control valve
105. Normally closed exhaust valve 108 is inserted in exhaust pipe
107. Steam supply pipe 109 and air supply pipe 110 extend from
portions of blow pipe 85 between flow control valve 105 and heater
106 sequentially in an air flow direction. Pipes 109 and 110 are
connected to steam source 112 and air source 113 through flow
control valves 111, respectively.
The operation of heater 106 is controlled on the basis of a
temperature near a connecting portion between blow pipe 85 and
outlet port 45 of air locker 103. In this embodiment, heater 106 is
operated to heat the heating medium flowing toward the connecting
portion, i.e., outlet port 45 of air locker 103 to be 100.degree.
C. to 350.degree. C., and more preferably 180.degree. C. to
220.degree. C.
A separator, e.g., tangential separator 114 is inserted in a
downstream portion of blow pipe 85 with respect to air locker 103.
Air locker 115 having the same structure as that of air locker 103
is disposed at the outlet of separator 114. Rotary drum type
humidifier 116 having the same structure as that of humidifier 1 is
arranged below air locker 115. A charging port of humidifier 116 is
located immediately below air locker 115 and receives the tobacco
material discharged from air locker 115. The tobacco material is
then charged in humidifier 116. Humidifying nozzle 117 is arranged
in humidifier 116 in the same manner as in humidifier 11. Nozzle
117 is connected to a water/steam source (not shown). Conveyor 118
extends from the discharge port of humidifier 116 and is connected
to a device of the subsequent stage (not shown).
In the expanding apparatus according to the first embodiment
described above, the tobacco material dampened in humidifier 1 is
continuously supplied to impregnation vessel 10 through preparatory
vessel 7, second rotary valve 66, intermediate vessel 14, and first
rotary valve 42. Since impregnation vessel 10 is filled with the
high-pressure impregnating gas of carbon dioxide, during feeding of
the tobacco material by screw conveyor 89 to delivery port 84 of
vessel 10, the tobacco material is impregnated with the
impregnating gas, i.e., carbon dioxide gas.
The tobacco material impregnated with the impregnating gas in
impregnation vessel 10 is continuously discharged from delivery
port 84 of vessel 10 to blow pipe 85 through third rotary valve 91,
large-diameter pipe portion 87, fourth rotary valve 100, and air
locker 103.
The heating medium as a mixture of air supplied from blower 104 and
steam flows in blow pipe 85, so that the tobacco material
impregnated with carbon dioxide gas and supplied to blow pipe 85 is
blown toward separator 114. During blowing, since the heating
medium is heated to a predetermined temperature by heater 99, the
impregnated tobacco material is abruptly heated by heat from the
heating medium. Carbon dioxide impregnated in the tobacco material
is evaporated from the tobacco material. That is, a large amount of
impregnating gas, e.g., carbon dioxide gas is discharged from the
tobacco material. Evaporation of carbon dioxide gas causes
expansion of the tobacco material. The expanded tobacco material is
fed with air and reaches separator 114. The tobacco material is
separated from the heating medium by separator 114 and is charged
in humidifier 116 through air locker 115. The tobacco material
whose water content is reduced to 2% to 6% by expansion is finally
dampened to have a water content of 12% in humidifier 116.
Thereafter, the tobacco material is transferred from the outlet of
humidifier 116 to conveyor 118 and is fed to the next device along
conveyor 118.
Since the expanding apparatus according to the present invention
uses carbon dioxide gas, the pressure of the impregnating gas in
impregnation vessel 10 is preferably set to, e.g., 30 kg/cm.sup.2
(gauge pressure) as in the first embodiment in order to effectively
impregnate the tobacco material with carbon dioxide. In order to
continuously perform impregnation in impregnation vessel 10, the
tobacco material must be continuously supplied to vessel 10 and the
impregnated tobacco material must be continuously discharged from
vessel 10. In order to satisfy the above needs, according to the
first embodiment, first and second rotary valves 42 and 66 are
arranged between preparatory vessel 7 and impregnation vessel 10,
and third and fourth rotary valves 91 and 100 are arranged between
vessel 10 and blow pipe 85. Therefore, the tobacco material can be
continuously supplied to vessel 10 and continuously discharged
therefrom while vessel 10 is kept at a high pressure. In the first
embodiment, two rotary valves are arranged between preparatory
vessel 7 and impregnation vessel 10 and similarly two rotary valves
are arranged between vessel 10 and pipe 85 to reduce a pressure
difference between inlet and outlet ports 44 and 45 of each rotary
valve. As a result, a pressure load acting on each rotary valve can
be reduced.
According to the first embodiment, since intermediate vessel 14 is
arranged between preparatory vessel 7 and impregnation vessel 10,
i.e., between first and second rotary valves 42 and 66, pressure
variations in impregnating gas between first and second rotary
valves 42 and 66 upon operation of first and second rotary valves
42 and 66 can be absorbed by the volume of intermediate vessel 14.
Therefore, the pressure variations in impregnating gas to be
transmitted within vessel 10 can be minimized. In addition, screw
conveyor 18 is arranged in intermediate vessel 14 to discharge the
tobacco material therefrom. Screw conveyor 18 discharges the
tobacco material and effectively minimizes the pressure variations
in intermediate vessel 14. In other words, as screw conveyor 18 is
arranged inside intermediate vessel 14, transmission of pressure
variations in vessel 14 can be prevented by screw conveyor 18. As a
result, the pressure variations transmitted to impregnation vessel
10 can be effectively prevented.
The impregnation treatment performed in impregnation vessel 10
causes generation of absorption heat and adsorption heat. In
practice, the tobacco material in intermediate vessel 14 is
slightly impregnated with carbon dioxide gas. Therefore, the
tobacco material in vessel 14 also generates absorption heat and
adsorption heat. For this reason, the expanding apparatus of the
first embodiment includes cooling jackets 80 for impregnation
vessel 10, intermediate vessel 14, and first to fourth rotary
valves, an undesirable increase in temperature of the impregnating
gas can be prevented by the coolant supplied to the cooling jackets
80. Impregnation of the tobacco material with the impregnation gas
can be effectively performed while the temperature of the vessel is
kept constant.
Regarding cooling of the tobacco material in intermediate vessel
14, as is apparent from first rotary valve 42 (FIG. 2) arranged
between intermediate vessel 14 and impregnation vessel 10, when
each pocket 58 of first rotary valve 42 is disconnected from
communication hole 48and connected to communication hole 48j, the
impregnating gas having a gauge pressure of 18 kg/cm.sup.2 is
supplied to vessel 14 through communication hole 48j and
communication pipe 54. Since the pressure of the impregnating gas
in vessel 14 is kept at a gauge pressure of 15 kg/cm.sup.2, a
pressure difference between the impregnating gas supplied from
first rotary valve 42 to intermediate vessel 14 and the pressure in
vessel 14 is 3 kg/cm.sup.2 (gauge pressure). The impregnating gas
supplied from first rotary valve 42 to intermediate vessel 14 is
subjected to heat-insulating expansion due to the pressure
difference, thus effectively cooling the interior of intermediate
vessel 14. If cooling in vessel 14 is satisfactory by a cooling
behavior based on heat-insulating expansion of the impregnating
gas, cooling jacket 73 of vessel 14 may be omitted.
At expanding apparatus according to a second embodiment of the
present invention will be described with reference to FIG. 6. The
same reference numerals as in the expanding apparatus of the first
embodiment denote the same parts and functions in the expanding
apparatus of FIG. 6, and a detailed description thereof will be
omitted.
In the expanding apparatus of the second embodiment, a portion
between preparatory vessel 7 and impregnation vessel 10 is
constituted by a cylindrical pipe member or vertical convey pipe
11.
Remote-controlled first ball valve 122 is inserted in convey pipe
11 on the preparatory vessel 7 side to open/close convey pipe 11.
Remote-controlled second ball valve 123 is inserted in convey pipe
11 on the impregnation vessel 10 side to open/close convey pipe 11.
Therefore, a portion of convey pipe 11 is defined between the first
and second ball valves 122 and 123 and functions as a first
pressure equalizer chamber 121. When first and second ball valves
122 and 123 are closed, equalizer chamber 121 is fluid-isolated
from the preparatory and impregnation vessels 7 and 10.
In the second embodiment, delivery pipe 86 for connecting
impregnation vessel 10 and blow pipe 85 is constituted by a
vertical pipe member. Third ball valve 126 is inserted in delivery
pipe 86 on the impregnation vessel 10 side to open/close delivery
pipe 86. Fourth ball valve 127 is inserted in delivery pipe 86 on
the blow pipe 85 side to open/close delivery pipe 86. A portion of
delivery pipe 86 between third and fourth ball valves 126 and 127
is therefore defined as a second pressure equalizer chamber 125.
When third and fourth ball valves 126 and 127 are closed, second
pressure equalizer chamber 125 is isolated from vessel 10 and pipe
85.
In the second embodiment unlike in the first embodiment,
high-pressure tank 29 stores an impregnating gas or carbon dioxide
gas having a gauge pressure of 16 kg/cm.sup.2 or more. The
impregnating gas is supplied from tank 24 to impregnating vessel 10
through heat exchanger 33 and pressure control valve 34. Pressure
control valve 34 supplies the impregnating gas having a gauge
pressure of 15 kg/cm.sup.2 to impregnation vessel 10.
High-pressure tank 29 is connected to first pressure equalizer 121
through first pressure supply pipe 128 branched from a downstream
portion of impregnating gas supply pipe 32 with respect to heat
exchanger 33. Pressure control valve 129 and solenoid valve 130 are
sequentially inserted in first pressure supply pipe 128 from the
heat exchanger 33 side. Valve 129 sets the pressure of the
impregnating gas supplied to first pressure equalizer 121 through
first pressure supply pipe 128 at a pressure substantially equal to
that of impregnation vessel 10 and preferably a pressure slightly
higher than that of vessel 10, e.g., in the range of 15.5
kg/cm.sup.2 to 16 kg/cm.sup.2. First exhaust pipe 131 extends from
first pressure equalizer 121. Pipe 131 is connected to recovery gas
holder 24. Solenoid valve 132 and, if necessary, pressure control
valve 133 are sequentially inserted in pipe 131 from the first
pressure equalizer chamber 121 side. In the second embodiment,
purge gas supply pipe 134 extends from a downstream portion with
respect to heat exchanger 33. Pipe 134 is connected to preparatory
vessel 7. Pressure control valve 135 is inserted in purge gas
supply pipe 134. Valve 135 supplies the impregnating gas having a
pressure slightly higher than that of atmosphere, thereby filling
vessel 7 with the impregnating gas.
Second pressure supply pipe 136 extends from second pressure
equalizer 125. Pipe 136 is connected to a downstream portion of
pipe 32 with respect to heat exchanger 33. Solenoid valve 137 and
pressure control valve 138 are sequentially inserted in second
pressure supply pipe 136 from the second pressure equalizer 125
side. Valve 138 sets the pressure of the impregnating gas supplied
to second pressure equalizer 125 through second pressure supply
pipe 136 at a pressure substantially equal to the pressure of the
gas in impregnation vessel 10 and preferably a pressure slightly
lower than that in vessel 10, e.g., in the gauge pressure range of
14 kg/cm.sup.2 to 14.5 kg/cm.sup.2. Second pressure equalizer 125
is connected to recovery gas holder 24 through second exhaust pipe
139. Solenoid valve 140 and, if necessary, pressure control valve
141 are inserted in exhaust pipe 139 from the second pressure
equalizer 125 side.
An operation of the expanding apparatus according to the second
embodiment of the present invention will be described below.
The tobacco material supplied to preparatory vessel 7 through
humidifier 1 is fed to the upper portion of convey pipe 11 by screw
conveyor 17. The upper portion of convey pipe 11 and preparatory
vessel 7 are filled with the impregnating gas supplied through
purge gas supply pipe 134.
Thereafter, first ball valve 122 is opened to cause the upper
portion of convey pipe 11 to communicate with first pressure
equalizer 121. Assume that first pressure equalizer 121 is filled
with the impregnating gas having a pressure substantially equal to
the atmospheric pressure. When first ball valve 122 is open, screw
conveyor 17 in preparatory vessel 7 is simultaneously driven. The
tobacco material in the upper portion of convey pipe 11 is pushed
out by the tobacco material stored in preparatory vessel 7 and is
supplied to first pressure equalizer 121. First ball valve 122 is
then closed to separate first pressure equalizer 121 from the
preparatory vessel 7 side.
Thereafter, solenoid valve 130 is energized to supply the
impregnating gas to first pressure equalizer 121 through first
pressure supply pipe 128 and pressure control valve 129. The
pressure of the impregnating gas in first pressure equalizer 121
becomes slightly higher than that of impregnation vessel 10. At
this time, solenoid valve 130 is closed. While the impregnating gas
is being supplied to first pressure equalizer 121, a new tobacco
material is supplied from preparatory vessel 7 to the upper portion
of convey pipe 11.
Second ball valve 123 is then opened to tobacco material from
second pressure equalizer 121 to impregnation vessel 10. Since the
pressure of first pressure equalizer 121 is slightly higher than
that of vessel 10, the tobacco material in second pressure
equalizer 121 is smoothly supplied to vessel 10 due to a pressure
difference between second pressure equalizer 121 and impregnation
vessel 10 upon opening of second ball valve 123.
The tobacco material supplied in impregnation vessel 10 is
impregnated during movement along screw conveyor 89 inside vessel
10. After the tobacco material is supplied from first pressure
equalizer 121 to impregnation vessel 10, second ball valve 123 is
closed and solenoid valve 132 is opened, thereby returning the
impregnating gas from first pressure equalizer 121 to recovery gas
holder 24 and hence reducing the pressure of first pressure
equalizer 121 to the atmospheric pressure. Thereafter, solenoid
valve 132 is closed. Therefore, a preparatory operation of
receiving a new tobacco material to first pressure equalizer 121 is
completed.
During desired impregnation in impregnation vessel 10, solenoid
valve 137 is opened to supply the impregnating gas to second
pressure equalizer 125 through second pressure supply pipe 136 and
pressure control valve 138. When the pressure of the impregnating
gas in second pressure equalizer 125 becomes lower than that in
impregnation vessel 10, solenoid valve 137 is closed. Therefore, a
preparation for receiving the impregnated tobacco material from
impregnation vessel 10 to second pressure equalizer 125 is
completed.
When third ball valve 126 is opened, the impregnated tobacco
material is supplied from impregnation vessel 10 to second pressure
equalizer 125. In this case, a pressure difference between
impregnation vessel 10 and second pressure equalizer 125 is
present, so that transfer of the impregnated tobacco material from
vessel 10 to pressure equalizer 125 can be smoothly performed.
When the impregnated tobacco material is supplied to second
pressure equalizer 125, third ball valve 126 is closed and second
pressure equalizer 125 is separated from vessel 10.
Solenoid valve 140 is opened to return the impregnating gas from
second pressure equalizer 125 to recovery gas holder 24. The
pressure in second pressure equalizer 125 is decreased to about the
atmospheric pressure and then solenoid valve 140 is closed.
When the pressure of second pressure equalizer 125 is reduced to
the atmospheric pressure, fourth ball valve 127 is opened to
discharge the impregnated tobacco material from second pressure
equalizer 125 to blow pipe 85. During blowing of the tobacco
material through blow pipe 85, the impregnated tobacco material is
expanded in the same manner as in the first embodiment. The
pressure near the outlet of fourth ball valve 127 during discharge
of the impregnated tobacco material from second pressure equalizer
125 to blow pipe 85 is set to be a negative pressure a compared
with the pressure in blow pipe 85 due to the flow of the heating
medium in blow pipe 85. Therefore, the impregnated tobacco material
can be smoothly supplied from equalizer 125 to pipe 85. When all
the impregnated tobacco material is discharged from equalizer 125,
fourth ball valve 127 is closed.
As is apparent from the above description, in the same manner as in
the first embodiment, continuous impregnation of the tobacco
material can be achieved in the second embodiment. In addition, in
the second embodiment unlike in the first embodiment, the rotary
valves need not be used, thus simplifying the structure and
allowing easy maintenance.
An expanding apparatus according to a third embodiment of the
present invention is shown in FIG. 7. The expansion apparatus of
the third embodiment uses liquefied carbon dioxide in place of
carbon dioxide gas as an impregnating agent, unlike in the first
and second embodiments. The same reference numerals as in the first
and second embodiment denote the same parts and members in the
third embodiment, and a detailed description thereof will be
omitted.
In the third embodiment, liquefied carbon dioxide tank 22 is
connected to supply tank 151 through supply pump 150. Pump 150 is
actuated in accordance with a surface level of liquefied carbon
dioxide stored in supply tank 151. Therefore, tank 151 always
stores a predetermined amount of liquefied carbon dioxide having a
high pressure.
Supply tank 151 is connected to impregnation vessel 10 through
impregnating gas supply pipe 152. Cooler 153, pressure reducing
valve 154, and flow control valve 155 are sequentially inserted in
pipe 152 from the supply tank 151 side. Valve 155 controls a flow
rate of liquefied carbon dioxide supplied to vessel 10, thereby
maintaining the surface level of liquefied carbon dioxide in vessel
10 at a predetermined level. As is apparent from FIG. 7, vessel 10
is obliquely disposed such that the other end thereof is located in
the upper position.
Pressure reducing valve 154 reduces the pressure of liquefied
carbon dioxide to be supplied into impregnation vessel 10, i.e.,
the pressure of the impregnating agent into, e.g., a gauge pressure
of 10 kg/cm.sup.2 to 50 kg/cm.sup.2. In the third embodiment, the
pressure is reduced to 30 kg/cm.sup.2 in the same manner as in the
first embodiment. Cooler 153 cools the impregnating liquid to a
temperature which inhibits evaporation of the liquid even if the
pressure of the impregnating liquid is reduced.
Carbon dioxide gas, i.e., the impregnating gas having a gauge
pressure of 30 kg/cm.sup.2 is supplied from impregnation vessel 10
to intermediate vessel 14 through first rotary valve 42 and
communication pipe 54 in the same manner as in the first
embodiment. The impregnating gas is then supplied to preparatory
vessel 7 through second rotary valve 66 and communication pipe 70.
Therefore, preparatory vessel 7 is filled with the impregnating
gas. The pressure of the impregnating gas in intermediate vessel 14
is set to be a gauge pressure of 15 kg/cm.sup.2 by pressure control
valve 61 inserted in return pipe 59.
Recovery gas holder 24 is connected to liquid receiver 156 through
condensing pipe 157. Strainer 158, compressor 159, and condenser
160 are sequentially inserted in condensing pipe 157 from the
recovery gas holder 24 side. Condenser 160 cools and liquefies
carbon dioxide gas supplied from recovery gas holder 24. Liquid
receiver 156 stores liquefied carbon dioxide cooled to almost the
same temperature as that in supply tank 151. Liquid receiver 156 is
connected to supply tank 151 through pipe 161. Circulation pump 162
is inserted in pipe 161. Atmospheric release pipe 163 is connected
to liquid receiver 156. Air purge valve 164 is inserted in
atmospheric release pipe 163. Valve 164 is opened when an air
concentration in liquid receiver 156 exceeds a predetermined level,
thereby exhausting air from liquid receiver 156.
Impregnating gas pipe 163 extends from recover gas holder 24.
Strainer 164, compressor 165, and gas tank 166 are sequentially
inserted in impregnating gas pipe 163 from the recovery gas holder
24 side. High-pressure purge pipe 64 with pressure reducing valve
65 and medium-pressure purge pipe 68 with pressure reducing valve
69 are branched from downstream portions of pipe 163 with respect
to gas tank 166. Compressor 165 causes gas tank 166 to store the
impregnating gas having a gauge pressure of 30 kg/cm.sup.2.
In the third embodiment, large-diameter pipe portion 87 of delivery
pipe 86 of the first embodiment is replaced with evaporating unit
167. Evaporating unit 167 has basically the same structure as that
of impregnation vessel 10. However, unlike vessel 10, unit 167 is
horizontally disposed. Evaporating unit 167 is cooled to the same
temperature as that of vessel 10. The impregnated tobacco material
discharged from vessel 10 is supplied to evaporating unit 167
through third rotary valve 91. Excessive liquefied carbon dioxide
as the impregnating liquid attached to the tobacco material
impregnated therewith is evaporated. The impregnating gas generated
in this manner returns to recovery gas holder 24 through pipe 88,
return pipe 59, and pressure control valve 61. The impregnated
tobacco material in evaporating unit 167 is discharged through
fourth rotary valve 100 by screw conveyor 169 driven by motor 168.
The evaporation process of the excessive impregnating liquid in
evaporating unit 167 can be controlled by varying the evaporation
time of the impregnated tobacco material in unit 167.
Referring to FIG. 7, circulation piping between each cooling jacket
80 and coolant tank 37 is not illustrated for illustrative
convenience.
According to the expanding apparatus of the third embodiment,
unlike in the first and second embodiments, liquefied carbon
dioxide can be used in impregnation of the tobacco material in
impregnation vessel 10. In addition, even if liquefied carbon
dioxide is used, impregnation and expansion of the tobacco material
can be continuously performed.
When the impregnated tobacco material is delivered from
impregnation vessel 10 to blow pipe 85 through delivery pipe 86, a
pressure acting on the impregnated tobacco material is reduced
stepwise when the tobacco material sequentially passes through
third rotary valve 91, evaporating unit 167, and fourth rotary
valve 100. Therefore excessive liquefied carbon dioxide attached to
the tobacco material can be sufficiently evaporated, and liquefied
carbon oxide attached to the tobacco material is not converted into
dry ice. As a result, the impregnated tobacco material can be
smoothly guided from impregnation vessel 10 to blow pipe 85 through
delivery pipe 86. Impregnation and expansion of the tobacco
material can be continuously performed.
The present invention is not limited to the first to third
embodiments described above. Various changes and modifications may
be made within the spirit and scope of the invention. In the first
embodiment, the pressure of impregnating gas is increased in the
path between the preparatory vessel to the impregnation vessel and
the pressure of the impregnating gas is reduced in the path between
the impregnation vessel and the blow pipe. For this purpose, the
rotary valves are used. However, in the second embodiment, the
pressure of the impregnating gas is increased and decreased by
using ball valves. The rotary valve may be combined with the ball
valves to increase and decrease the pressure of the impregnating
gas.
In the first embodiment, two rotary valves are inserted between
preparatory vessel 7 and impregnation vessel 10 and two rotary
valves are inserted between impregnation vessel 10 and blow pipe 85
to increase and decrease the pressure of the impregnating gas.
However, in the same manner as in the second embodiment, when the
pressure of the impregnating gas in impregnating vessel 10 is set
to be a gauge pressure of 15 kg/cm.sup.2, only one rotary valve or
a one-stage rotary valve can be used to increase and decrease the
pressure of the impregnating gas. The present invention is not
limited to the number of rotary valves.
Finally, the materials to be expanded in the first to third
embodiments are tobacco materials. however, the material used in
the expanding apparatus of the present invention is not limited to
the tobacco material but can be extended to favorite items (e.g.,
tea and green tea), vegetables, grains (e.g., rice), or foodstuffs
(e.g., seaweed).
The expanding apparatus of the present invention makes it possible
to use carbon dioxide as an impregnating material in place of a
Freon gas for applying an expanding treatment to a tobacco
material. Since the expanding treatment can be applied continuously
to a tobacco material by using carbon dioxide, the apparatus of the
present invention is highly effective for improving the cigarette
productivity and lowering the manufacturing cost of cigarettes.
* * * * *